How environmental contaminants can have different effects on women and men.

Industrial activities release a plethora of contaminants, some of which are better studied than others. Fracking, for instance, can release trace elements and volatile organic compounds (VOCs).

Professor Élyse Caron-Beaudoin is a researcher at the University of Toronto Scarborough where she studies the effects of these contaminants on surrounding communities in British Columbia’s Peace River Valley, a region where natural gas exploitation by fracking is a predominant industry.

Benzene and toluene, which are VOCs, can cause birth and developmental defects. But there had been no epidemiological studies examining the association between fracking and birth outcomes in the region until Caron-Beaudoin investigated this question during her postdoctoral fellowship at the Université de Montréal’s School of Public Health. During the same period, Caron-Beaudoin and her colleagues launched the Exposures in the Peace River Valley (EXPERIVA) study, a biomonitoring assessment that aims to measure the levels of exposure to various contaminants associated with fracking in a cohort of pregnant women.

“Historically, a lot of research was conducted using exclusively male animals, and women were often excluded from clinical trials,” says Caron-Beaudoin.

Sara Brosché, a science advisor at the International Pollutants Elimination Network, has observed the same gap in scientific and policy discussions. In December, she led the publication of a report that addressed the distinct effects of chemicals on women.

“Women are generally more disproportionally impacted by exposure to chemicals and wastes and have less access to participation in decision making,” writes Brosché.

The report considers the sex-differentiated effects for various contaminants. That is, their effects with respect to biological sex assigned at birth, and their effects with respect to gender, which is a social construct. These contaminants included lead in paint, manufactured nanomaterials, endocrine-disrupting chemicals (EDCs), pharmaceutical pollutants, and per- and polyfluoroalkyl substances (PFAS).

PFAS, also known as ‘forever chemicals’ because of their persistence in both the environment and in humans, are used in the making of electronics, household items, and personal care products. In several studies, PFAS have been shown to mimic estrogen, which can cause unexpected changes in how cells grow and develop. It is also linked to lower birth weights and menstrual irregularities.

The gendered effects of PFAS are most evident in cosmetic products, where they are used as solvents and stabilizers. Yet, according to Brosché, studies that quantitatively analyse the presence of PFAS in cosmetics are limited. Nanomaterials and persistent organic pollutants are also used in cosmetic products that generally target women.

Health Canada’s biomonitoring studies — which are used to measure chemicals in tissues — found PFOA and PFOS, two forms of PFAS, in more than 99 per cent of their participants. Still, PFAS aren’t as regulated as other contaminants on the market in Canada.

EDCs, a category that encompasses substances such as toxic metals, phthalates, and bisphenols, are another major cause for concern according to Brosché’s report. These substances have been studied separately but the challenge is that they tend to disrupt the endocrine system in tandem.

In addition to outlining the gender- and sex-specific effects and exposures of contaminants on women, Brosché points to the need for more women involved in forming policies around how these substances are managed. Caron-Beaudoin echoes this sentiment.

“I would like to see gender balance and participation in the decision processes regarding contaminants and chemicals management in Canada,” she says.

As Caron-Beaudoin notes, Canada has made some progress in investigating how sex and gender affect health outcomes. For instance, the Canadian Institutes of Health Research works to integrate sex and gender-based factors in health research.

While her own research doesn’t account for gender, it does factor participants’ biological sex assigned at birth.

“Biological differences occurring on the sex spectrum can have significant impacts on the levels of exposure to environmental contaminants,” says Caron-Beaudoin.